dma

[Hans Petter Selasky]

On 11/08/15 11:22, AlexHully wrote:
> Hi,
>
> I would like a clarification for dma.
>
> The context: most dma capable devices have 32 bits address range.
> Is it correct that, if there was no 3G/1G mapping in the kernel, or that kernel low memory could map 4Gb memory, one could choose any free addresses in that low memory to set up a dma buffer?
>
> That would avoid all the mapping hassle, and performance cost associated.
>

I've seen USB controllers only supporting 2G address range.

--HPS